#!/usr/bin/python # -*- coding: utf-8 -*- # † from collections import namedtuple from math import log10 Tup = namedtuple('Tup', 'p, q, t') #def isqrt(n): # if n < 0: # raise ValueError('square root not defined for negative numbers') # if n == 0: # return 0 # a, b = divmod(n.bit_length(), 2) # x = 1<<(a+b) # while True: # y = (x + n//x)//2 # if y >= x: # return x # x = y def newtonsqrt(q, n, init): x, m, c3 = init, 0, 3 c3 <<= n while m != x: m = x x *= c3 - ((m * m * q) >> n) x >>= n + 1 return x def isqrt(s): n = s.bit_length() b = 8192 if n & 1: b += 1 x = 1<<(b/2) m = n / 6 while 1: w = s >> (n-b) x = newtonsqrt(w, b, x) y = 2 * m if b + y > n: break b += y x <<= m x <<= (n-b) / 2 x = newtonsqrt(s, n, x) * s >> n return x def pi_chudnovsky_bs(digits): C = 640320 C3_OVER_24 = C**3 // 24 def bs(a, b): if b - a == 1: if a == 0: p = q = 1 else: p = (6*a-5)*(2*a-1)*(6*a-1) q = a*a*a*C3_OVER_24 t = p * (a*545140134 + 13591409) if a & 1: t = -t else: m = (a + b) // 2 am = bs(a, m) mb = bs(m, b) p = am.p * mb.p q = am.q * mb.q t = mb.q * am.t + am.p * mb.t return Tup(p, q, t) DIGITS_PER_TERM = log10(C3_OVER_24/6/2/6) n = int(digits/DIGITS_PER_TERM + 1) _, Q, T = bs(0, n) sq = isqrt(10005 * 10**(2*digits)) return (Q*426880*sq) // T N = 200000 res = str(pi_chudnovsky_bs(N)) S = raw_input().replace('.', '') for i in xrange(N, -1, -1): if S[i] != res[i]: print S[i], res[i] break